Load transfer device



R. C. YEOMAN May 3U, 1950 Patented May 30, 1950 LOAD TRANSFER DEVICE Ray Cyrus Yeoman, Lufkin, Tex., assigner to Texas Foundries, Inc., Lufkin, Tex., a oorporaf tien of TeXcS Application March 28, 1945, Serial No. 585,237

(Cl. S34-8) 6 Claims.

This invention relates to load transfer devices and more particularly to devices for transferring loads between adjacent Slabs 0f concrete or the like.

One of the objects ci the invention is to provide a load transfer device which is simple and inexpensive to manufacture and installand which will effectively transfer both vertical and horizontal loads between the slabs.

Another object is to provide a load transfer device which is resilient to yield horizontally under expansion `and contraction of the slabs.

Still anoti-iel1 object is to provide` a load transfor device formed of wires or rods twisted together to transmit vertical loads between the slabs and to yield to permit relative horizontal movement of the slabs.

Still another object is to provide a load transfer device formed of a single sheet or plate having outwardly projecting leg pOrtions to be imbedded in the slabs and a deformable central portion to accommodate relative horizontal Inovement of the slabs,

The above and other objects and advantages of the invention will be more readily apparent from the following description when lead in connection with the accompanying drawing, in which- Figure l is a partial vertical section through adjacent slabs connected by a load transfer device embodying the invention;

Figure 2 is a horizontal section through Figure 1;

Figure 3 is a View similar to Fig-ure l of a slightly modified construction;

Figure 4 is a. partial perspective section showing another construction;

Figure 5 is a view sifn'lilar to Figure 1 showing an alternative form of load transfer device; and

Figure 6 is a partial perspective view of the load transfer device of Figure 5.

As shown in Figures l and 2, the load transfer device is adapted to connect adjacent slabs in and H of concrete or the like which `are provided with a compressible nller `strip i2 between the adjacent faces. The filler strip l2 may be of any desired compressible construction and is preferably forrned with openings therethrough to ac.- conimodate the load transfer devices.

The load transfer devices of Figures 1 and 2 comprise a pair of wires or rods 1.3 twisted to.- gether at their central portions with their ends extending angularl-y into the slabs Hl and I! to be anchored therein.` As shown, each wire makes one complete 10.01) so that its opposite @ed p0rtions are imbedded in different slabs. The twisted central portions of the wires ar'e preisrably covered `with yielding plastic material` ld such as rubber, asphalt composition, or` the like to hold back the plastic concrete during setting and to compress when the slabs expand to permit their faces to move closer together.

With the device installed, as s hown,`any vertical load on one of the slabs will be transmitted through the wires i3 and through the twisted central portions thereof to the opposite slab to hold the upper surfaces of the slabs `substantially in exact alineinent at all times. When the slabs expand so that their faces tend to movetogether, the twisted portions of the wires tend to twist slightly and will flex to accommodate such movement, the material il! compressing at this time. As the SlabS contract so that their adjacent faces tend to separate, the twisted portions of the wires will bend to twist more tightly together. This operation `will continue until the wires are tightcned to the maximum. extent at which time iurther separation of the slab faces willbe prevented to prevent disengagement of the slab faces from the i'lller strip l2.

In the construction shown in Figure 3, the load transfer device is `similarly formed by two wires l5 twisted together at their central portions and each having one and one-half loops .so that the end portions of each wire are in the same slab. The twisted central portions are covered with yielding plastic material it to accommodate com.- pression of the joint. Vertical loads will be transinitted through the wires and through the intertwisted portions thereof to maintain the upper surfaces of the slabs irl. substantiallg7 the same plane while horizontal movement of the slabs will be accommodated by exing of the twisted portions and compression of the material I6 in the same manner as described in connection with Figures l and 2.

In the construction shown in Figure 4, the load transfer device is formed by four wires, Il, I, iii and 2li, all twisted together at their central portions and covered by yielding plastic material iii. The wires may be so twisted that the ends or each wire are imbedded in each slab `or in dif: ferent slabs as desired. This construction funo tions in substantially the same manner as the constructions of Figures 1 and 3J except that it can carry slightly greater loads due to the inf creased number of wires or rods employed.

Figures 5 and 6 illustrate a diilerent type of load transfer .device gior .connecting adjacent slabs .2.2 eed 2.3 having a compr-@Sable .filler `Strip 24 between their adjacent faces. The load transfer device is formed by a single strip or plate of sheet metal having its edge portions slit and bent out in opposite directions to form legs 25 to be irnbedded and anchored in the slabs. The legs connect to the central portion 26 of the strip or plate which lies vertically between the slab faces. The central portion 26 is partially slit between the adjacent legs as indicated at 21. Preferably, the legs are bent in such a manner as to provide short horizontal bearing portions 2S next adjacent the central portion 26, as shown.

When this unit is installed in the slabs in the position shown in Figure 5 yielding strips 29 are placed between the opposite faces of the central portion 26 and the adjacent slab faces. Preferably, the strips 29 are secured to the opposite faces of the central portion 26 for convenience in handling.

Vertical loads between the slabs will be transferred through the legs 25 and the central portion 26 without permitting appreciable movement of the slabs relative to each other due to the relatively short parts of the legs which extend from the slab faces and the fact that such loads are transmitted vertically through the central portion 26. Upon expansion of the slabs, the central portion 26 of the plate will be distorted, this action being assisted by the slits 2'! and by compression of the strips 29 to permit the slab faces to move closer together. When the slabs contract, the central portion 26 of the plate will distort in the opposite direction to permit the slab faces to separate. It will be noted, however, that distortion of the strip is limited so that the slab faces can separate only to a predetermined limited extent which is not sufficient to break the seal between the filler strip 24 and the slabs.

While several embodiments of the invention have been shown and described in detail, it will be understood that these are illustrative onli and are not intended as a definition of the scope of the invention, reference being had for this purpose to the appended claims.

What is claimed is:

1. A load transfer device adapted to be imbedded in adjoining concrete slabs for transferring loads therebetween and for limiting separation thereof comprising a substantially vertically rigid and horizontally yieldable body portion having oppositely disposed legs extending outwardly and upwardly from the top of the body portion and oppositely disposed legs extending outwardly and downwardly from the bottom of the body portion, the legs on one side of the body portion adapted to be imbedded in one of the adjacent slabs land the legs on the other side of the body portion adapted to be imbedded in the,` other adjacent slab with the body portion vertically disposed therebetween for transferring vertical loads between the slabs, and a plastic material of substantial thickness about the body portion providing for limited horizontal yielding of the body portion and adapted to provide limited separation of the adjacent slabs.

2. A load transfer device adapted to be imbedded in adjoining concrete slabs for transferring loads therebetween and for limiting separation thereof comprising a plurality of elongated wires twisted together at their central portions to provide a substantially vertically rigid and horizontally yieldable body portion and with their end portions providing oppositely disposed wire legs extending outwardly and upwardly from the top of the twisted wire body portion and oppositely disposed wire legs extending outwardly and downwardly from the bottom of the twisted wire body portion, the wire legs on one side of the twisted Wire body portion adapted to be imbedded in one of the adjacent slabs and the Wire legs on the other side of the twisted wire body portion adapted to be imbedded in the other adjacent slab with the twisted wire body portion vertically disposed therebetween for transferring vertical loads between the slabs, and a plastic material of substantial thickness about the twisted wire body portion providing for limiting horizontal yielding thereof and adapted to provide limited separation of the adjacent slabs.

3. A load transfer device `adapted to be imbedded in adjoining concrete slabs for transferring loads therebetween and for limiting separation thereof comprising a plurality of elongated wires twisted together through substantially 360 at their central portions to provide a substantially vertically rigid and horizontally yieldable body portion and with their end portions providing oppositely disposed wire legs extending upwardly and outwardly from the top of the twisted wire body portion and oppositely disposed wire legs extending downwardly and outwardly from the bottom of the twisted wire body portion, the wire legs of each elongated wire extending from opposite sides of the twisted wire body portion, the wire legs on one side of the twisted wire body portion adapted to be imbedded in one of the adjacent slabs and the wire legs on the other side of the twisted wire body portion adapted to be imbedded in the other adjacent slab with the twisted wire body portion vertically disposed therebetween for transferring vertical loads between the slabs, and a plastic material of substantial thickness about the twisted wire body portion providing for limited horizontal yielding thereof and adapted to provide limited separation of the adjacent slabs.

4. A load transfer device adapted to be imbedded in adjoining concrete slabs for transferring loads therebetween and for limiting separation thereof comprising a plurality of elongated wires twisted together through substantially 450 at their central portions to provide a substantially vertically rigid and horizontally yieldable body portion and with their end portions providing oppositely disposed wire legs extending outwardly and upwardly from the top of the twisted wire body portion and oppositely disposed wire legs extending outwardly and downwardly from the bottom of the twisted wire body portion, the wire legs of each elongated wire extending from the same side of the twisted wire body portion, the wire legs on one side of the twisted wire body portion adapted to be imbedded in one of the adjacent slabs and the wire legs on the other` side of the twisted wire body portion adapted to be imbedded in the other adjacent slab with the twisted wire body portion vertically disposed therebetween for transferring vertical loads between the slabs, and a plastic material of substantial thickness about the twisted wire body portion providing for limited horizontal yielding thereof and adapted to provide limited separation of the adjacent slabs.

5. A load transfer device adapted to be imbedded in adjoining concrete slabs for transferring loads therebetween and for limiting separation thereof comprising a sheet having its upper and lower edge portions slitted to form tongues which are alternately bent outwardly in opposite directions to provide a substantially vertically rigid and horizontally yieldable body portion and oppositely disposed legs extending outwardly and upwardly from the top of the body portion and oppositely disposed legs extending outwardly and downwardly from the bottom of the body portion, the legs on one side of the body portion adapted to be imbedded in one of the adjacent slabs and the legs on the other side of the body portion adapted to be imbedded in the other adjacent slab with the body portion vertically disposed therebetween for transferring Vertical loads between the slabs, and a plastic material of substantial thickness about the body portion providing for limited horizontal yielding of the body portion and adapted to provide limited separation of the adjacent slabs.

6. In combination with a pair of adjoining concrete slabs, ya load transfer device imbedded in the adjoining slabs and comprising a substantially vertically rigid and horizontally yieldable body portion having oppositely disposed legs extending outwardly and upwardly from the top of the body portion and oppositely disposed legs extending outwardly and downwardly from the bottom of the body portion, the legs on one side of the body portion being imbedded in one of the adjacent slabs and the legs on the other side of the body portion being imbedded in the other adjacent slab and the body portion being vertically disposed between the adjacent slabs for transferring vertical loads therebetween, and a plastic material of substantial thickness about the body portion for spacing the body portion from the adjacent slabs to provide for limited horizontal yielding of the bddy portion and limited separation of the adjacent slabs.

RAY CYRUS YEOIMAN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 749,765 Wight Jan. 19, 1904 1,495,022 Langer May 20, 1924 1,780,588 I-Ieltzel Nov'. 4, 1930 2,075,234 Schulz Mar. 30, 1937 2,093,718 Fremont Sept. 21, 1937 2,103,894 Bussmann Dec. 28, 1937 2,125,857 Fischer Aug. 2, 1938 2,183,484 Webb Dec. 12, 1939 2,256,930 Willard Sept. 23, 1941 2,278,834 Crede Apr. 7, 1942 2,299,670 Westcott Oct. 20, 1942 2,330,214 Heltzel Sept. 28, 1943 2,349,983 Musall May 30, 1944 FOREIGN PATENTS Number Country Date 479,029 Great Britain 1938 

